Sure. Create a new virtual CD with just the music tracks (you need a blank track 1, as mixed data/audio CDs have the data as "track 1). It will be a lot smaller than the whole game CD, but certainly not a few MBs.
Remember that SE4 will use any audio CD in the drive as a music source. You can control which tracks are used for normal game tracks, which are combat, etc. in Settings.txt.
Originally posted by Imperator Fyron: Remember that SE4 will use any audio CD in the drive as a music source. You can control which tracks are used for normal game tracks, which are combat, etc. in Settings.txt.
Indeed. My soundtrack for SEIV is a CD I made of music I "borrowed" from Freelancer.